A vortex reactor has a reaction chamber, which is typically mostly cylindrical, but may have other shapes. The reaction chamber has an exhaust or nozzle end and a closed or fuel inlet end, usually at opposite ends of the reaction chamber.
Vortex reactors in the prior art employ one or two vortexes to create specific fluid flow fields in the reaction chamber that accomplish specific goals. Typically, fuel and oxidizer fill the inside of the reaction chamber from its nozzle to its fuel inlet before it is combusted.
The present invention employs three vortexes in the reaction chamber forming and changing the flow fields to accomplish specific goals. The third vortex forms a greater concentration of the fuel and oxidizer in a mixing region adjacent to the fuel inlet and it optionally serves as a means to create a double-ended moving plasma arc in the mixing region to improve the performance of the reactor. Because of the rapid propagation of combustion due to the enhanced mixing and double end, rotating and traveling arc, more complete combustion occurs. Rapid and complete combustion enables greater diversity in fuel, enhanced combustion efficiency and stability and inherently avoids potentially disruptive explosions created when ignition occurs in a reaction chamber filled with unignited fuel.
In a vortex reactor, combustion occurs in the reaction chamber in a first vortex of fluid flow spiraling outward around the axis of the reaction chamber and towards the nozzle end. This vortex is typically induced by the swirling introduction of fuel, or a fuel and oxidizer mixture, into the combustion chamber.
Fuel as used herein and as is typical in the art may include gases, liquids, solids such as particles or powders, and reagents. If just fuel is introduced, then it is subsequently mixed with an oxidizer, for example air, within the reaction chamber and ignited. The gases resulting from ignition and combustion along with any uncombusted fuel continue to exit out the nozzle end of the reaction chamber in a vortex of spiraling helical flow. Incomplete mixing is often a cause of unburned fuel being discharged from the reaction chamber and any mechanism to encourage more thorough mixing can add to reactor efficiency by reducing the discharge of unburned fuel. This first vortex is also referred to herein as the primary vortex.
A reverse vortex reactor introduces a second vortex, which is a circumferential vortex fluid flow, typically air or other oxidizer, around the wall or periphery of the reaction chamber starting at the nozzle end of the reaction chamber and spiraling towards the fuel inlet end. U.S. Pat. No. 6,298,659 to W. H. Knuth, et al. on Oct. 9, 2001 is representative of this prior art.
In a reverse vortex reactor, the first vortex is in the center of the reaction chamber and the second vortex is at the wall of the reaction chamber. A reverse vortex reactor essentially adds the second vortex creating double helical vortex flow fields moving in opposite directions. This second vortex is a circumferential fluid flow that spirals at the periphery of the reaction chamber away from the nozzle end toward the closed end in a direction reverse to the flow in the first vortex. When the second or reverse vortex fluid flow reaches the closed end, it wells up back towards the nozzle end combining with and taking the path of the first vortex rotating about the axis of the reaction chamber. A fluid flow welling up around the axial center enhances mixing of fuel with the oxidizer. A chemical reaction, such as combustion, may then be induced to take place in a central region of the reaction chamber keeping the walls or periphery cool by the spiraling action of the reverse circumferential fluid flow at the wall of the reaction chamber. Essentially, the walls are protected from combustion by the reverse vortex fluid flow occupying the wall region in the chamber.
The triple helical flow vortex reactor of the present invention is new in the field of vortex flow field reactors. It introduces a third vortex, which is a circumferential vortex fluid flow, typically air or other oxidizer and optionally including fuel, around the wall or periphery of the reaction chamber starting at the fuel inlet end of the reaction chamber and spiraling towards the nozzle inlet end. This third vortex opposes the circumferential fluid flow in the second vortex. The opposing circumferential fluid flow in the third vortex changes the reaction chamber flow fields considerably, creating a vigorous mixing region at the fuel inlet end of the reaction chamber and substantially improving the efficiency of combustion. The enhanced mixing is itself a significant improvement to the prior art because it concentrates the combustible fuel and oxidizer to a smaller volume within the relation chamber that is more efficiently ignited. In addition to a reaction motor, other applications for the triple helical flow vortex reactor include a reactor for solid particle melting in specific gas environment with further deposition on different surfaces, and a reactor for mixing or combining chemicals.
Further efficiencies are obtained in an embodiment of the invention by adding capability to generate spatial plasma arcs to induce ignition within the reaction chamber. The means of the present invention to create a spatial plasma arc is new to the field of reaction chambers. It is essentially an electrical arc generated between an anode and cathode in which the end of the arc at the anode and the end of the arc at the cathode travel and rotate or orbit around the relation chamber within the mixing zone. The plasma arc is expanded and rotated by action of the fluid flow. In the preferred embodiment, the fluid flow from the third vortex is utilized for expanding and rotating the arc. Such arc expansion contributes to extending electrode lifetime, and has even greater benefit in combustion efficiency and reactor size and weight reduction, which are desirable in applications such as an aircraft and rocket engines.
Spatial arcs in accordance with an embodiment of the invention typically cycle or transition from glow to spark and back on a nanosecond time scale. Such short time scale, expanding discharges deliver a substantial improvement to the prior art by reducing the voltage required for spark ignition of combustion gases, lowering average electrical power consumption, simultaneously releasing very high pulsed energy, which consequently speeds the rate of combustion, and improves combustion stability. For example, with the spark current of about 200 amperes and pulse duration of about 100 nanoseconds, instantaneous power in the spark reaches a megawatt. One more important environmental factor in reactor combustion is arc temperature and its interaction time with the burning mixture. Too high a temperature or too long an arc interaction with the fuel increases formation of nitrogen oxides, which are the polluting exhaust gases. The invention reduces formation of nitrogen oxides by enabling a low-power arc with nanosecond discharges.
Conventional methods of producing arc plasmas in reaction chambers, for example, plasma torches, such as plasmatrons, are based on constricting either one or both ends of an arc discharge to a particular location, which tends to generate small volumes of plasma at high temperatures, delivering poor combustion and a low overall efficiency of the vortex reactor. It also tends to quickly burn out one or both electrodes.
The prior art teaches a means to enable an expanding arc by locating an electric arc discharge symmetrically in the center of a hollow rotating cylinder so that the arc begins to expand radially outwards due to viscous drag forces. Discussion of this prior art is in U.S. Pat. No. 4,801,435 to J. K. Tylko on Jan. 31, 1989. Tylko also describes a second method using a plasma torch acting as a cathode, which is made to orbit in a circular path and at a small angle with the vertical, projecting the arc to a downstream annular anode. Tylko teaches a means for making one end of an arc travel using sequential energization of plasma torches or electromagnetic circulation.
These prior art techniques are generally disfavored because they add considerable weight to the reactor, typically cause rapid failure of the reaction chamber and add further complicated equipment that is susceptible to failure. Because the plasma arc in the present invention permits both ends of the plasma arc to travel as a function of the vortex flow, no complicated equipment is needed, no added weight is involved, the life of the anode and cathode are extended over that achievable in the prior art and increases the volume of the arc in the mixing region positively affects combustion efficiency, which translates to greater fuel diversity potential for the reactor.
Prior art vortex reactors generally perform poorly with particulate matter fuels. The particles tend to interfere with the formation and energy transfer from a plasma arc. Because the plasma arc of the present invention operates on non-steady state pulses of nanosecond duration, the very high instantaneous power transfer minimizes problems attendant with particulate matter fuels.
Accordingly, the present invention will serve to improve the prior art by changing the number of vortex flow fields to create an enhanced mixing zone. It further improves the state of the art in plasma ignition of the fuel. These improvements deliver a vortex reactor with enhanced capability for fuel diversity, improved operating efficiency, lower environmental pollution, and significantly lower voltages, and consequently power, required to initiate combustion. A significant advantage is a vortex reactor that is lighter and smaller than present reactors with the same power output.